Former President Jimmy Carter, who is on a three-nation tour of west Africa, says he is confident the crippling Guinea worm disease will be wiped out.

Speaking Tuesday in Togo, Mr. Carter says he is optimistic the goal of completely eradicating Guinea worm disease is close to being achieved.

"Guinea worm is one of the two diseases on earth now that is specifically designated to be completely eradicated from the face of the earth," he said. "The other one is polio, and we believe that Guinea worm is going to be the next one."

Polio has been resurfacing in West and Central Africa, after Islamic leaders in northern Nigeria blocked several vaccination drives, claiming the vaccine was tainted.

But Guinea worm, known in the region as "fiery serpent," has been steadily decreasing since 1986, when the U.S.-based Carter Center started fighting it alongside the United Nations and the U.S. government.

From an estimated 3.5 million cases in 1986, the U.S. Centers for Disease Control reports, the number of infected people dropped to about 35,000 last year, most of them in Sudan and West Africa.

Guinea worm is contracted when people drink stagnant water contaminated by tiny water fleas carrying infected larvae.

The larvae can grow up to a meter long inside the body, before emerging through painful blisters on the skin, formed usually on the legs.

Many sufferers tend to seek relief from the burning pain by immersing in water. There the blisters burst, releasing a new generation of millions of larvae.

The only treatment is to remove the worm by winding it around a small stick and pulling it out, bit by bit.

Infection can be prevented by boiling water and filtering it through tightly woven cloth before drinking it, or by drinking water from a safe source.

Mr. Carter is visiting Togo, Ghana and Mali on his trip, where several thousand cases remain. He says Togo has been the most successful in wiping out the disease because of an aggressive government led-campaign that includes public education.

The national coordinator of Togo's program, Komi Amegboh, says it is also important to treat each case individually.

He says every new identified patient is immediately taken to a specialized center and kept there until he or she fully recovers.

Ghana also has made considerable progress in eradicating the disease, especially in villages where volunteers act as advisors. One of the volunteers, American Anne Heggen, says she has seen tremendous improvement in one northern village, after she started educating people and helping them dig wells.

"This village that we are in right now, last year at this time, they had over 100 cases, and this year, they have about four, and you just see the people are happier, they are more productive," he said. "They are just working and able to get to go to school. So, you do see the benefits of getting rid of Guinea worm."

Mr. Carter says eradicating Guinea worm can also inspire doctors and health workers around the world to get rid of other diseases, such as tuberculosis, malaria and HIV-AIDS, affecting mostly the poorest countries.